The overall objective of the research is to define the kinetics of uptake, distribution, metabolism, and excretion of inhaled lipid-soluble vapors in man, by a set of differential equations, using predictable constants. The physical, chemical, and biological constants needed will be determined by simple experiments. Solution of the equations will be facilitated by a program for a large digital computer. To verify the pharmacokinetic model, the experimental conditions of suitable published studies in man will be simulated, and their results compared with the calculated data. Further verification will be done by animal experiments. The pharmacokinetic model for the rat will be elaborated, and the predicted concentrations in rats sacrificed at selected time intervals following exposure. The described pharmacokinetic model will be used to design the proper monitoring of industrial data; to predict the cumulation of inhaled compounds and their metabolites in the body; to explain the role of certain physiological factors (body build, pulmonary ventilation, tissue perfusion); and to formulate guidelines for the prediction of the uptake, distribution, metabolism, and secretion of new noxious compounds introduced in industry. Initial plans are to use toluene, trichloroethylene, carbon disulfide, and methylene chloride in the study.